Hydraulic disruption of solids



April 1, 1941. w. F, COURT 2,236,895

HYDRAULIC .'DISRUPTION OF SOLIDS Filed Nov. 4, 1958 2 Sheets-Sheet lInvenl'or-,Willom Frederick (LourdL April l, 1941. W. F. couRT HYDRAULICDISRUPTION 0F SOLIDS Filed Nov. 4, 1958 2 Sheets-Sheet 2 Invenforf: WlomFederck Cour? Patented Apr. 1, `1941 HYDRAULIC .DISRUPTION F SOLIDWilliam Frederick Court, Webster Groves, Mo., as-

signor to Shell Development Company, San Francisco, Calif., acorporation o! Delaware Application November 4, 1938, Serial No.238,848

' (ci. 21o- 44) .5 Claims.

This invention relates to the hydraulic disruption of solid masses, suchas coke, by means of water jets, and is particularly concerned withimprovements in the step of clarifying the used Water tol permit itsbeing recirculated to the water jets. Y

In my copending application Serial No. 191,685, filed February 21, 1938,of which this is a continuation-in-part, I have described particularlythe process for cleaning vessels which contain carbonaceous material,such as deposits of coke produced by the carbonization of hydrocarbonoils, particularly reaction and coking chambers employed in petroleumlcracking plants and the like, and asphaltic materials, especially thesolid, brittle kinds, by means of water jets. In accordance with thatprocess, the body of carbonaceous material to be removed is disrupted byjets of Water,applied in several steps, thewater and l'umps of solidsfalling from the bottom of the yvessel or. chamber into a receptacle.such as a car. Most of the coke settles to the bottom of the car, andonly a suspension of relatively ne particles of carbonaceous solid inWater is washed over the side or through openings in the side or bottomof the car. The suspension is collected in a trough and led into asettling basin provided with a screen. Most of the solids are settledand ltered out ofthe water which is then recirculated through the pumpsand jetting nozzles. y

In practicing this method, itwas found that the separationof theneparticles of carbonaceous solids from the water to be recirculated tothe jetting operation is necessary to prevent Wear and tear on theconduits, pumps, and nozzles, and prevent costly repairs andinterruptions. The presence of substantial quantities of-coke andsimilar carbonaceous matter in the water rapidly causes erosion andresults in a drop in efficiency of the high pressure pumps required inthis method. Wear and tear of the pump and nozzles increase the load on"the driver actu- .ating the pumpl and thus materially increase the costof the operations. In some cases, the nozzle tips become plugged due tothe presence of so much fine coke thatthe j et operation must be stoppedfor the purposeof cleaning nozzle tips.

Difculty has been experienced in clarifying the water which isrecirculated to the letting operation and in treating the' slurry ofcarbonaceousnes which is filtered or settled out in the clarificationsystem. The treatment of the slurry is necessary for recovering thewater for recirculation or the fines for utilization as a product..

It often was. sought to obtain as small a volume of the slurry aspractical to permit its disposal without too great a loss of water. Thisnecessitated the use of relatively large settling basins to provide asufiicient settling time and often resulted in an insuilicientclarification o'f the recirculated water. l

It is an object of this'invention to provide an improved method andapparatus for separating fine particles of carbonaceous solids fromwater which flows off during the disruption of carbona- -ceous depositsby means of Water jets, such as hydraulic decoking operations. It is.afurther object of the invention to provide a water clari- V cationsystem whichfis simple to operate and is capable of taking care offluctuations in the rate at which water is charged Iinto it. Stillanother object is to provide an improved method and apparatus forremoving carbonaceous depositsvfrom coke chambers and the like by meansof water jets in which the Wear on the hydraulic equipment and thedanger of stoppage due to solutions, emulsions, etc.

In accordance with the present invention, it was found 'that a slurry ofcarbonaceous nes and water, such as is withdrawn from the chamber beingcleaned or from -a settling basin, can be broken readily, i. e.,separated into water and coke, by owing it through a layer of. .largerparticles of carbonaceous material, such as the lump coke contained inone of the coke cars beneath the coke chamber. ,By this method, thewater introduced into. the settling and/or nitration unitswill containsmaller quantities offines than when the suspension is treated in theseunits without passing 'through the coke bed. Further, it was found thatlarger bodies of slurry can be clarified, thereby making it possible Vtorecirculate to the jetting operation a relatively higher proportion oiwater of improved clarity. It will be noted that the invention involvesthe flow of aslurry of water and fines through a coke bed, such slurrybeing derived either from' the chamber being cleaned, yor from thesettling and/0r ltration units, and that it may be applied to thetreatment of either type of slurry without t tion Serial No. 191,685,

the other, although in the preferred form of the invention, described indetail herein, both slurries are passed through the bedV of coke.

The invention may be understood from the following detailed descriptiongiven in connection with the accompanying drawings which are exemplaryonly, it being understood that the invention is not limited to thesespecific steps described lherein nor to the use of the particularapparatus illustrated in the drawings. In the drawings: i f

accesos faucets 26 into the coke car III. It was found Athat the slurrywas effectively broken and that Figure 1 is a schematic diagramillustrating one form of the invention, parts being shown in elevationand sectional elevation;

Figure 2 `is a perspective view of a preferred water-clarifyingequipment according to another form of the invention; and

Figure 3 is a vertical sectional view of the preliminary settling andscreening unit of Figure 2.

ReferringtoFigurel, I isacokechamberofa usual cracking or cokinginstallation, containing carbonacemis material to be removed, providedwith upper and lower manhole heads 2 and I; l is a vertical water feedpipe supported/by a tower. not shown, and supplied with water by hingedpipes i and i, riser pipe 1, and a high pressure pump 8. The water feedpipe I is vertically adjustable and carries .letting nozzles I.. whichmay be such as those described in my parent applicafor disrupting thecoke in the chamber I.

During the liett'ing operation the water disrupts the suspension throughthe 4holes I2 into the trench I3 was of substantially the same characteras that which flowed through these holes in the absence of the slurrywhich was recirculated via the conduit 25. By this method, it becomespossible not only to clarify the slurry and to recover -the coketherefrom, but to aid .the sedimentation in the settling tank Il,because it] is not necessary to reduce the volume of the slurry to assmall avolume as heretofore.

- The slurry in the conduit 25 may be introduced into the coke car illeither simultaneously with the water vand coke discharged from the cokechamber I, or separately into a coke car whichl has been lled previouslywith coke. As indicated heretofore. the treatment of the slurry fromvthe settling tank may be practiced independently of the step offiltering the slurry' from, the coke chamber I, it being possible toomit the latter step. Also, the bed of coke need not be in a ear, v butmay be a deposit of coke on a suitable screen or even in a basin,arranged to permit water to drain from the bottom. The connectionsbetween the manifold 22 and the settling tank are provided preferablywith valves. so that the slurry can be removed intermittently, as whenthe slurry has accumulated the carbonaceous material and a mixture ofwater containing suspended fines and larger lumps of coke falls Ithroughthe lower manhole l into a Il. A -screen II separates fines which do notSettle out ip the tank. The clarled water is i recirculated to thenonies by the pum-p l.

It will' be `noted that the slurry ofwater and suspended ilnes which isremoved from the lower manhole 3 together with the larger lumps of cokethroughthebedofcokeinthecar. Asa consequence. the slurry is brokenandthe water escaping through the openings I2 contains ai relativelysmaller quantity of fines than would vslurry whichispassedintothetrenchHandsettling tank I4 directly from whichthe lump coke hasbeen removedwithout now through a bed of cokef In the settling tank I4 the timerequired for sedimentation increases as the volume of thelowersuspensionoralurrylaycris view of the diiilculty of breaking thesetti slurry it was heretofore the practice to withdraw as containingsuspended iines, flows into. a settling tank Il equipped with over andunder baiiies I5,

in the tank to a height which will interfere with the proper operationof the tank. It was found :that the slurry can be readily pumped but itis very desirable to maintain a sufiiciently high ilow velocity in theconduits to avoid the deposition of coke therein. v

The settling tank Il is provided further prefv erably with one or moreskimmers 21 connected to the manifold 22 -by a conduit 28 for thepurpose of removing small particles of coke which oat on the surface ofthe water. In installationswherein floating coke is not encountered theskimmer 21 may be eliminated. The skimmer 21 is normally kept inoperation continuously during the operation of the settling tank. Air

agitating coils, like coils I3 described in Figure 2,

may also be provided.

In the preferred clarification system according to the invention thesuspension reinoved fm the zles as described in connection withFigure 1. A

- coke 'car 3l movable beneath the manholes or Inco much as possible ofthe water 'via the pump I.

Thhoftenresultedinanincompletesettling. with the consequence that therecirculated water in the pump I contained unduly large quantities offines. 'ro achieve the improved settling required w the construction ofexcessively large settling ba'-sinsandevenbythisexpedientitwasnotpossibletoeifecttherecirculationofailofthewater.

In'accordance with the present invention, I

withdrawthesettiedalurryfromthesettlingtank l il at one or more pointsIl. l. l. f manifold 22andconduit2lbythe .2l and discharge the slurryvia conduit 2l and;

tracks n is provided with openigs n at the bottom to permit a suspensionof coke and water to drain therefrom. The suspension flowing through theopening 33 and over the sides of the car'is collected by concrete apronsIl and directed into a trough beneath the tracks. The suspension flowsby gravity from-the trough into a lateral trench Il and into apreliminary settling and screening basin II, shown more particularlyinFigure 3. Thewaterpassesrstthrougha coarse screen 31 such as a screenprovided with openings one inch square to exclude coarse particles ofcoke, and then through a liner inclined screen 38. such as s screenprovided with '150 to 200 openings per square. such both screensextending entirelyacrossthebasin 38. Partof the suspended coke isremoved by settling'in the basin orbyiiltration by means ofthescreen 2Bthe partially cial-ined water is withdrawn by a conduit 39, clear waterpiim'p 40, and conduit 4I and is introduced into a settling tank 42. l

The settled slurry of coke is withdrawn from the bottom of the basin 36through an intake pipe 43 and flows Ithrough slurry pump 44 and conduit45 to the manifold 45, located parallel to the tracks 32. A skimmer 4'.'extending at its upper end across the entire wid-th of the settlingbasin is also connected to the slurry .pump 44 by means of a conduit 48.Fine particles of coke which float on the surface of the water arethereby removed to prevent accumulation of such bodies near the top ofthe screen 38.

A plurality of faucets 49 is provided on lthe manifold 46 located todischarge the slurry into the coke car '3L In an installation comprisinga plurality of coke chambers, the coke car may assume a position beneathany one chamber being cleaned or may stand idle over any portion of thetrough after it has received a bed of coke, and the faucets 49 arelocated so that the water from the manif-old 46 may be discharged intothe coke car in any one of its several positions, the faucets beingpreferably arranged so as to discharge the slurry at several points inthe coke car, as shown.

The settling tank 42 is provided with over and under baies 5U, 5|and'with a nnal settling chamber 52. The partially clarified waterintroduced by conduit 4I is fur-ther clarified in tank 42 and owedthrough a roller-typescreen 53, preferably of relatively fine mesh.After passing through the screen, the water enters a slotted intake pipe54 and .flows into a surge tank 55.

Further settling may take place in the surge tank and the clarifiedWater flows beneath and over the final' under and'over baliles 56,51,'and is discharged from the surge tank via conduit 58 and highpressure pump 59. Water from the pump 59 is flowed through a highpressure .riser pipe 6B to the jetting nozzles in the coke chamber beingcleaned.' as indicated in Figure 1. Fresh i water make up is introducedinto the surge tank 55 via conduit 6l, provided with a oat-conl trolledvalve 62 to maintain the level in the surge tank substantially constant.

It is desirable to keep the water level in the preliminary settlingbasin 35 substantially constant to prevent vthe pumps from running dry.This is effected by withdrawing water from the bottom of the surge tank55 vla a conduit 63 and oat-controlled valve 64. An overow line 55 isalso provided. By connecting the conduit B3 to.

the preliminary settling basin 35. A trough Il is attached to one sideof the settling tank 42, covered by a grating 12. When the accumulationof fine coke on the bottom of the tank 4between the bellies issuflicient to require cleaning, the

settling tank is emptied and the coke is manually removed and dumpedinto the trough from where it falls into a truck or similar conveyance.

an agitating con 1: is located at the bo tom of the chamber 52. When theaccumulation of coke at the bottom of the settling chamber is so greatas to interfere with the smooth functioning of the settling tank, ablast of air is emitted from the coil, thereby raising the coke to thesurface of the water` and permitting its withdrawal through the skimmer66. If desired, a similar lfskimmer and similar agitating coils may beprovided between adjacent ballles 50, 5l, thereby obviating the use ofthe trough 1I.

Moreover, slurry maybe withdrawn from the bottom of the settling tank atone or more points in the manner shown in Figure 1.

A by-pass line 15, provided with a valve 14, joinsmhe clear waterconduit 4| with the slurry conduit 45, permitting the liquids to bediverted when a part of the system is. shut down, or when a p art of thesystem is too full.

The method of operation will be apparent from the above description ofthe two forms of the water clarication system. It will be understoodthat when there is a series of coke chambers certain chambers will be inoperation for reacting products withdrawn from the cracking furnace,while usually not nore than one is being cleaned at one time. Thiscleaning operation, described more completely in my parent application,is usually conducted in several steps, and the rate 1 of flow of waterfrom the lower manholes is in terrupted, so that the surge tank shouldbe of sufficient size tc maintain the Water level in the preliminarysettling basin 36 and to provide a suicient volume of water for thejetting operation.

With regard to the skimmer 4l and the lower intake pipe 43, it may bestated that, while valves may be provided to proportion the relativeintakes into the slurry pump 44, no regulation is normally required, ithaving been found practical 4to obtain a proper balance between thesettled slurry and the surface slurry by a proper design of the relativecross-sectional areas and lengths of the pipes 43 and dil.

The expression slurry is, in the present speciflcation and claims,intended to include settled slurry and surface slurry, i. e., thematerial withdrawn from the bottom and the material withdrawn from thesurface of the water in a settling basin, as-well as the suspensionremoved from the coke chamber. While the method is particularly adaptedfor use in connection with the high pressure hydraulic removal of cokefrom vertical reaction chambers of the type used in a Dubbs crackinginstallation, it may also be used when other bodies of carbonaceoussolids are hydraulically disrupted.

I elaim as my invention: Y

l. A process vfor clarifying a slurry of liquid containing suspendedfines, produced by disruptcentrated slurry of. surface lines isvirithdrawn- 'from the surface of the liquid ln the settling zone, andboth slurries are flowed through said bed.

3. Apparatus for clarifying a slurry of'liq'uid containing suspendedfines produced by disrupting a body of solid material in a containerinto pieces by means of a water iet, comprising a receptacle adapted tocontain md of said disrupted solids, a settling basin', means for con#ducting a slurry from said receptacle to said basin, means forwithdrawing claried liquid from the settling basin, means forwithdrawing slurry from said basin, and means for conducting saidwithdrawn slurry to said receptacle vandl discharging it on the bed ofsolids therein.

4. Apparatus for clarifying a slurry 4of 1iquid containing. suspendedfines produced by disrupt- `ing a body of solid material in acontainerinto pieces by means of a water jet, comprising a receptacle adapted tocontain a body oflsaid disrupted solids, a settling basin, means forconducting a slurry from said receptacle tosaid basin, means forwithdrawing clarified liquid from the settling basin, nozzle means nearthe l; bottom of said basin for emitting a blast of a gas, a skimmerarranged to withdraw surface slurry from surface of the liquid in'lsaid.basin,

' and means forr conducting said withdrawn slurry to' said receptacleand discharging it onthe bed of solids therein. I Y

5. A process for clarifying a slurry of liquid containing suspended nes,produced by disrupting a body of solid materials in a container intopieces by means of a liquid jet, comprising the steps of accumulatingdisrupted solids in a bed,

yflowing said slurry through a sedimentation zone,

withdrawing liquid substantially freed from suspended fines from saidzone, withdrawing/a concentrated slurry of nes from said zone and owingsaid concentrated slurry through said bed'.

WILLIAM FREDERICK COURT.

